Microsoft KB Archive/247228

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Article ID: 247228

Article Last Modified on 5/18/2005


  • Microsoft SNA Server 4.0
  • Microsoft SNA Server 4.0 Service Pack 4
  • Microsoft Host Integration Server 2000 Standard Edition
  • Microsoft Host Integration Server 2000 Service Pack 1

This article was previously published under Q247228


When you open an SDLC connection with an Attachmate Advanced ISCA PCI adapter, the connection may stay pending, and the application event log may record the following error message:

Unable to Contact First Required Interrupt.

This problem occurs on some systems with a BIOS that assigns PCI interrupts to PCI adapters that are outside the ISA range of interrupt 1 through 15. This problem has been reported in the Compaq 3500 series.


To work around this issue, set the IRQ table to mapped IRQs. The following is an example of how to do this on a Compaq 3500. The key sequence to access the BIOS and the location of the bus settings may vary on other systems:

  1. Make sure that the adapter is installed in BUS 0. To determine if the adapter is in BUS 0, locate the processor. The first 4 slots that are located closest to the processor are typically the first bus, BUS 0. The PCI specification calls out 4 bus loads (single adapters).
  2. Press F10 during startup to access the BIOS on the Compaq 3500.
  3. Type CTRL-A to open the Advanced Features menu.
  4. Choose Review the Hardware Settings.
  5. In the View and Edit Details section, select the Full Table and Mapped option. This forces PCI devices to use IRQs 2 through 15.


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Keywords: KB247228